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    <title>Document</title>
    <style type="text/css">
        #class {
            margin: 0px auto;
            width: 500px;
            height: 500px;

        }

        td {
            border: solid 2px red;
            width: 100px;
            height: 100px;
            text-align: center;
            font-weight: bold;
        }
    </style>
    
    <script type="text/javascript">
        //setInterval: 班级回答问题
        function fn(){
            //获取随机数
            var num =  parseInt(Math.random()*41+1)   
             //获取对应的td对象
            var tdobj = document.getElementById('td'+num)
            //设置背景颜色
            tdobj.style.backgroundColor = 'red'
            // 将结果显示到span中
            document.getElementById('sp').innerText = '恭喜你，你被抽中了'+ tdobj.innerText;
        }

        function start(){
            //初始化背景
            for (let i = 1; i <= 42; i++) {
                var tdobj = document.getElementById('td'+i)
                tdobj.style.backgroundColor = 'white';
            }
             //抽奖开始，将span中的文本设置成：正在抽奖中...
            document.getElementById('sp').innerText='正在抽查中....'
            //设定定时器,1秒后出结果
            setTimeout(fn,1000);
        }
    </script>
</head>


<body>
    <div id="button" style="text-align:center;margin:50px">
        <button onclick="start()">抽查</button>
        <span id="sp"></span>
    </div>
    <table id="class">
        <tr>
            <td id="td1">郑玮喆</td>
            <td id="td2">庄云</td>
            <td id="td3">廖治先</td>
            <td id="td4">郑文源</td>
            <td id="td5">戴俊锋</td>
            <td id="td6">陈昊童</td>
        </tr>
        <tr>
            <td id="td7">谢金金</td>
            <td id="td8">占志新</td>
            <td id="td9">张淑芳</td>
            <td id="td10">刘永潘</td>
            <td id="td11">廖柏成</td>
            <td id="td12">郑宗帅</td>
        </tr>
        <tr>
            <td id="td13">李韦峰</td>
            <td id="td14">吴欣燕</td>
            <td id="td15">陈梅香</td>
            <td id="td16">陈立智</td>
            <td id="td17">袁贵森</td>
            <td id="td18">赵浩敏</td>
        </tr>
        <tr>
            <td id="td19">林世涛</td>
            <td id="td20">罗启恒</td>
            <td id="td21">卢国建</td>
            <td id="td22">黄柱菘</td>
            <td id="td23">陈鹏</td>
            <td id="td24">张耀仁</td>
        </tr>
        <tr>
            <td id="td25">陈华伟</td>
            <td id="td26">张正豪</td>
            <td id="td27">韦仲晓</td>
            <td id="td28">黄富贵</td>
            <td id="td29">陆建锋</td>
            <td id="td30">曾德森</td>
        </tr>
        <tr>
            <td id="td31">吴文龙</td>
            <td id="td32">陆利群</td>
            <td id="td33">黄雄</td>
            <td id="td34">王世财</td>
            <td id="td35">张先杰</td>
            <td id="td36">胡基耀</td>
        </tr>
        <tr>
            <td id="td37">马鑫涛</td>
            <td id="td38">李涛</td>
            <td id="td39">杨凌翔</td>
            <td id="td40">罗此东</td>
            <td id="td41">唐皓颖</td>
            <td id="td42">白婉婷</td>
        </tr>
    </table>

</body>
</html>